Re: [PATCH RFC v2 1/8] spi: dt-bindings: spi-peripheral-props: add spi-offloads property

From: David Lechner
Date: Thu May 23 2024 - 11:09:16 EST


On 5/23/24 9:57 AM, Nuno Sá wrote:
> On Thu, 2024-05-23 at 09:28 -0500, David Lechner wrote:
>> On 5/22/24 1:24 PM, Conor Dooley wrote:
>>> On Tue, May 21, 2024 at 09:54:39AM -0500, David Lechner wrote:
>>>> On Sun, May 19, 2024 at 7:53 AM Conor Dooley <conor@xxxxxxxxxx> wrote:
>>>>>
>>>>> On Fri, May 17, 2024 at 11:51:58AM -0500, David Lechner wrote:
>>>>>> On Thu, May 16, 2024 at 4:32 PM Conor Dooley <conor@xxxxxxxxxx> wrote:
>>>>>>> On Tue, May 14, 2024 at 05:56:47PM -0500, David Lechner wrote:
>>>>>
>>
>
> ...
>
>>
>> controller:
>> #spi-offload-cells = <2>: /* 1st cell = offload instance
>>                            * 2nd cell = trigger provider */
>>
>
> What about things like DMA? I'm mentioning it a lot because it's way more complex
> having it on the controller (from a SW perspective). But from an HW point of view,
> it's always very similar (if not the same) as your case A.
>

If we had a setup where there was more than one place that, e.g. the
RX stream from the offload could be piped, then I would add a 3rd
cell to describe that. If the hardware is fixed and the RX stream
always goes to a specific DMA channel, then it doesn't seem like we
need to describe that in the SPI controller node because the hardware
is fixed.